The present invention relates to a direct-view type display apparatus for forming a picture (i.e., an optical image) through modulating the light strength or intensity of a light emitted from a slight source (hereinafter, being abbreviated “light modulation”) by means of a light modulation unit, such as, a liquid crystal panel, etc., and it relates to, in particular, a lighting apparatus for achieving an increase of contrast of the display picture by adjusting an amount of the lights to be irradiated from the light source mentioned above onto the light modulation unit.
In recent years, accompanying with stoppage of the terrestrial analog television (TV) broadcasting, which is planned in the year 2011, in Japan, a direct-view type video display apparatus of a large or wide screen is spreading, widely, which can receive the terrestrial digital television (TV) broadcasting of high definition (for example, 1,920×1,080 pixels) that was already started.
In general, as a display panel to be used in the direct-view type video display apparatus is applied a PDP (Plasma Display Panel) or a liquid crystal panel, etc., for example, but the liquid crystal panel is inferior in the contrast (or being called “contract ratio”) thereof, by around a single digit, comparing to that of the PDP. Then, within the video display apparatus applying the liquid crystal panel therein is applied a light-modulation technology, for controlling a lighting apparatus of illuminating the liquid crystal panel from a rear surface thereof, upon basis of an averaged brightness a black level area and a white level area of the picture, which are detected from a video signal, and thereby increasing the contrast thereof.
As the technologies relating to the light-modulation are already known, for example, so-called a back-light control, for chaining an amount of lights emitted from the light source (for example, please see the following Patent Document 1), and a control for changing an amount of lights emitted from the light source by means of a liquid crystal panel (for example, please see the following Patent Document 2), etc.
[Patent Document 1] Japanese Patent Laying-Open No. 2006-30588 (2006); and
[Patent Document 2] Japanese Patent Laying-Open No. Hei 6-230364 (1994).